Processes and intermediate compounds for preparing guanidine and amidine derivatives

ABSTRACT

The invention relates to new compounds of general formula I  
                 
 
     or the pharmaceutically acceptable salts thereof, wherein  
     X=N-R 3  or CH-R 4 ,  
     Y=CH 2  or (CH 2 ) 2 ,  
     Z=O or H 2 ;  
     and R 1 , R 2 , R 3 , R 4  and Ar have the meanings given in the specification, and the preparation and use thereof. The new compounds are valuable neurokinin (tachykinin) antagonists.

APPLICATION DATA

[0001] This application is a divisional of U.S. Ser. No. 09/320,974 U.S. Pat. No. 6,103,719.

[0002] The invention relates to new guanidine and amidine derivatives of general formula I

[0003] and the pharmaceutically acceptable salts thereof, processes for preparing them and pharmaceutical compositions containing these compounds. The compounds are valuable neurokinin (tachykinin) antagonists.

[0004] The abbreviations used in this specification and claims are explained as follows:

[0005] Boc=t-butyloxycarbonyl

[0006] DC=thin layer chromatogram

[0007] DMF=dimethylformamide

[0008] EE=ethyl acetate

[0009] FAB-MS=fast atom bombardment mass spectroscopy

[0010] RT=room temperature

[0011] TBTU=O-benzotriazolyl-tetramethyluronium tetrafluoroborate

[0012] TEA=triethylamine

[0013] THF=tetrahydrofuran

[0014] A simplified format is used for the formulae. In the representations of compounds, all CH₃ substituents are indicated by a hyphen, e.g.

[0015] The invention relates to new guanidine and amidine derivatives of general formula I

[0016] or the pharmaceutically acceptable salts thereof, wherein

[0017] X denotes N—R³ or CH—R⁴, wherein R³ denotes

[0018] wherein R⁵, R⁶ and R⁷

[0019] independently of one another denote H, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, alkanoyl, benzoyl, heteroaryl, dialkylamino, dialkylaminoalkyl, trialkylammoniumalkyl, cyano, alkyloxycarbonyl, aralkyloxycarbonyl, OH, O-alkyl or O-aryl, wherein the alkyl groups contain 1 to 5 carbon atoms, the cycloalkyl groups contain 3 to 6 carbon atoms, the alkenyl groups contain 2 to 5 carbon atoms, aryl denotes phenyl, or phenyl or naphthyl substituted by methyl or halogen (F, Cl, Br, I); or R⁵ and R⁶ or R⁶ and R⁷ together form the group (CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅— or —(CH₂)₂O(CH₂)₂; or R³ denotes

[0020] and R⁴ denotes

[0021] wherein R⁵ to R⁷ are as hereinbefore defined and

[0022] R⁸=H, alkyl with 1 to 5 carbon atoms or cycloalkyl with 3 to 6 carbon atoms or

[0023] R⁷+R⁸ together form the group —(CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅— or —(CH₂)₂O(CH₂)₂—; or R⁴ denotes

[0024] wherein R⁵ is as hereinbefore defined;

[0025] Y denotes CH₂ or (CH₂)₂;

[0026] Z denotes O or H₂;

[0027] Ar denotes unsubstituted or mono- to 5-substituted phenyl, or unsubstituted or mono- or disubstituted naphthyl [wherein the substituents of the phenyl and naphthyl independently of one another denote halogen (F, Cl, Br, I), OH, (C₁₋₄)alkyl, O—(C₁₋₄)alkyl, CF₃, OCF₃ or NR⁹R¹⁰ (wherein R⁹ and R¹⁰ independently of one another denote H, methyl or acetyl)] or Ar is phenyl substituted by —OCH₂O— or —O(CH₂)₂O—;

[0028] R¹ denotes phenyl(C₁₋₄)alkyl or phenyl(C₁₋₄)alkanoyl or naphthyl(C₁₋₄)alkyl or naphthylacetyl, wherein phenyl may be substituted by 1 to 3 substituents, wherein the substituents independently of one another denote halogen (F, Cl, Br, I), (C₁₋₄)alkyl, O—(C₁₋₄)alkyl, CF₃, OCF₃ or NR¹⁹R²⁰ (wherein R¹⁹ and R²⁰ independently of one another denote H, methyl or acetyl); and

[0029] R² denotes H, (C₁₋₄)alkyl, (C₃₋₆)cycloalkyl, CH₂COOH, —CH₂C(O)NH₂, OH or phenyl(C₁₋₄)alkyl.

[0030] The compounds according to the invention are valuable neurokinin (tachykinin) antagonists which have both substance P antagonism and also neurokinin-A- or neurokinin-B-antagonistic properties. They are useful for the treatment and prevention of neurokinin-mediated diseases.

[0031] Compounds of general formula I may contain acid groups, mainly carboxyl groups, and/or basic groups such as amino functions, for example. Compounds of general formula I may therefore occur as internal salts, salts with pharmaceutically acceptable inorganic acids such as hydrochloric acid, sulphuric acid, phosphoric acid, sulphonic acid or organic acids (such as, for example, maleic acid, fumaric acid, citric acid, tartaric acid or acetic acid) or as salts with pharmaceutically acceptable bases such as alkali metal or alkaline earth metal hydroxides or carbonates, zinc or ammonium hydroxides or organic amines such as e.g. diethylamine, triethylamine, triethanolamine, etc.

[0032] The compounds according to the invention may occur as racemates, but may also be obtained as pure enantiomers, i.e. in the (R) or (S) form. Compounds which occur as racemates or in the (S) form are preferred.

[0033] Results of investigations into the compound according to the invention:

[0034] The receptor affinity for the NK₁ receptor (substance P receptor) is determined on human lymphoblastoma cells (IM-9) with cloned NK₁ receptors, by measuring the displacement of ¹²⁵-labelled substance P. The K₁ values thus obtained show the efficacy of the compounds. Example no. K_(i) [nMol/L] 1 0.45 2 0.30 3 0.20 4 0.53 5 6.28 6 0.88 7 1.45 8 0.19 9 0.14 10 0.12 12 0.32 27 1.11 28 4.16 29 0.87 30 0.17 31 8.96 32 0.20 33 13.25 34 0.37 35 0.78

[0035] The compounds according to the invention are valuable neurokinin (tachykinin) antagonists which have both substance P antagonism and also neurokinin-A- or neurokinin-B-antagonistic properties. They are useful for the treatment and prevention of neurokinin-mediated diseases:

[0036] For preventing or treating inflammatory or allergic diseases of the respiratory tract such as asthma, chronic bronchitis, hyperreactive respiratory tract, emphysema, rhinitis, cough,

[0037] of the eyes, such as conjunctivitis and iritis,

[0038] of the skin, such as dermatitis in contact eczema, urticaria, psoriasis, sunburn, insect

[0039] bites, itching, sensitive or hypersensitive skin,

[0040] of the gastro-intestinal tract such as gastric and duodenal ulcers, ulcerative colitis, Crohn's disease, irritable bowel, Hirschsprung's disease,

[0041] of the joints, such as rheumatoid arthritis, reactive arthritis and Reiter syndrome;

[0042] for treating diseases of the central nervous system, such as dementia, Alzheimer's disease, schizophrenia, psychoses, depression, headache (e.g. migraine or tension headaches), epilepsy; Parkinson's disease, stroke,

[0043] for treating Herpes zoster and postherpetic pain, tumours, collagenoses, dysfunction of the urinary tract, haemorrhoids, nausea and vomiting, triggered by radiation or cytostatic therapy, for example, or movement and pain of all kinds.

[0044] The invention therefore also relates to the use of the compounds according to the invention as curative agents and pharmaceutical preparations which contain these compounds. They are preferably used in humans. The compounds according to the invention may be administered by intravenous, subcutaneous, intramuscular, intraperitoneal or intranasal route, by inhalation, by transdermal route, if desired with the aid of iontophoresis or enhancers known from the literature, and by oral route.

[0045] For parenteral administration the compounds of formula I or the physiologically acceptable salts thereof are brought into solution, suspension or emulsion, optionally with the substances conventionally used for this, such as solubilisers, emulsifiers or other adjuvants. Suitable solvents include, for example: water, physiological saline solutions or alcohols, e.g. ethanol, propandiol or glycerol, sugar solutions such as glucose or mannitol solutions or a mixture of different solvents.

[0046] Moreover, the compounds may be administered by means of implants, e.g. of polylactide, polyglycolide or polyhydroxybutyric acid or intranasal preparations.

[0047] Preferred compounds of general formula 1 are those wherein

[0048] X denotes N—R³ or CH—R⁴, wherein

[0049] R³ denotes

[0050] wherein R⁵, R⁶ and R⁷ independently of one another denote H, alkyl, cycloalkyl, aryl, aralkyl, alkanoyl, benzoyl, dialkylamino, dialkylaminoalkyl, trialkylammoniumalkyl, cyano, alkyloxycarbonyl, aralkyloxycarbonyl, OH, O-alkyl or O-aryl,

[0051] wherein the alkyl groups contain 1 to 4 carbon atoms, the cycloalkyl groups contain 3 to 6 carbon atoms, aryl denotes phenyl or phenyl substituted by methyl or halogen (F, Cl, Br, I); or R⁵ and R⁶ or R⁶ and R⁷ together form the group —(CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅— or —(CH₂)₂O(CH₂)₂; or R³ is

[0052] wherein R⁵ to R⁷ are as hereinbefore defined and

[0053] R⁸=H, alkyl with 1 to 5 carbon atoms or cycloalkyl with 3 to 6 carbon atoms or

[0054] R⁷+R⁸ together form the group —(CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅— or —(CH₂)₂O(CH₂)₂—;

[0055] Y denotes CH₂ or (CH₂)₂;

[0056] Z denotes O or H₂;

[0057] Ar denotes unsubstituted or mono- to 5-substituted phenyl [wherein the substituents of the phenyl independently of one another denote halogen (F, Cl, Br, I), OH, (C₁-C)alkyl, O—(C₁₋₄)alkyl, CF₃, OCF₃ or NR⁹R¹⁰ (wherein R⁹ and R¹⁰ independently of one another denote H, methyl or acetyl)] or Ar is phenyl substituted by —OCH₂O— or —O(CH₂)₂O—;

[0058] R¹ denotes phenyl(C₁-C₄)alkyl or phenyl(C₁-C₄)alkanoyl, wherein phenyl may be substituted by 1 to 3 substituents, wherein the substituents independently of one another denote halogen (F, Cl, Br, I), (C₁₋₄)alkyl, O—(C₁₋₄)alkyl, CF₃, OCF₃ or NR¹⁹R²⁰ (wherein R¹⁹ and R²⁰ independently of one another denote H, methyl or acetyl); and

[0059] R² denotes H, (C₁₋₄)alkyl or (C₃₋₆)cycloalkyl.

[0060] Particularly preferred are those compounds wherein

[0061] X denotes N—R³ or CH—R⁴, wherein

[0062] R³ denotes

[0063] R⁴ denotes

[0064] and R⁵ to R⁶, Z, Ar, R¹ and R² are as hereinbefore defined, and Y denotes CH₂.

[0065] Of these compounds, the preferred ones are those wherein Z is oxo, and/or

[0066] Ar is unsubstituted phenyl, particularly those wherein

[0067] Ar is phenyl mono- or disubstituted by halogen, preferably

[0068] Ar is dichlorophenyl; and/or wherein R¹ denotes substituted phenylacetyl (preferably 3,4-di-trifluoromethylphenyl-acetyl) or wherein R¹ is substituted phenylethyl, wherein the phenyl is substituted by 2 substituents which, independently of one another, denote halogen (F, Cl, Br, I), (C₁₋₄)alkyl or CF₃, particularly wherein the substituents of the phenyl are CF₃, CH₃ or F, (preferably wherein the two substituents of the phenyl are CF₃); and/or wherein R² is (C₁₋₄)alkyl, preferably wherein R² is methyl.

[0069] Compounds of formula I are preferred wherein the group

[0070] is

[0071] One aspect of the invention relates to compounds of formula I wherein X denotes the group CR⁴, wherein

[0072] R⁴ is

[0073] wherein

[0074] R⁵, R⁶R⁷ and R⁸ independently of one another denote H, alkyl with 1 to 4 carbon atoms or cycloalkyl with 3 to 6 carbon atoms; or

[0075] R⁷ and R⁸ together form the group (CH₂)₂, (CH₂)₃, (CH₂)₄ or (CH₂)₅. Compounds wherein R⁵ and R⁶ denote H and R⁷ and R⁸ together form the group (CH₂)₂ or those wherein R⁵ and R⁶ denote H and R⁷ and R⁸ are cyclohexyl are preferred.

[0076] Another important aspect of the invention relates to compounds of formula I wherein X is the group NR³ wherein

[0077] R³ is

[0078] wherein

[0079] R⁵ and R⁶ independently of one another denote H, alkyl with 1 to 4 carbon atoms, cycloalkyl with 3 to 6 carbon atoms, phenyl, or phenyl, benzyl or benzoyl substituted by methyl or halogen (F, Cl, Br, I), CN, alkyloxycarbonyl (wherein the alkyl group contains 1 to 4 carbon atoms), benzyloxycarbonyl, alkoxy with 1 to 4 carbon atoms or dialkylamine (wherein the alkyl groups contain 1 to 4 carbon atoms),

[0080] R⁷ denotes H or alkyl with 1 to 4 carbon atoms; or R⁵ and R⁶ or R⁶ and R⁷ together form the group (CH₂)₂, (CH₂)₃, (CH₂)₄ or (CH₂)₅; or R⁶ and R⁷ together form the group —(CH)₂—O—(CH₂)₂—.

[0081] Of these compounds, the preferred ones are those wherein

[0082] a) R⁵ and R⁶ independently of one another denote H, alkyl with 1 to 4 carbon atoms, cycloalkyl with 3 to 6 carbon atoms, phenyl, phenyl, benzyl or benzoyl substituted by methyl or halogen (F, Cl, Br, I);

[0083] R⁷ is H or alkyl with 1 to 4 carbon atoms or R⁵ and R⁶ or R⁶ and R⁷ together form the group (CH₂)₂, (CH₂)₃, (CH₂)₄ or (CH₂)₅; or R⁶ and R⁷ together form the group —(CH₂)₂—O—(CH₂)₂—;

[0084] b) R⁵ and R⁶ independently of one another denote H, alkyl with 1 to 4 carbon atoms, cyclohexyl, phenyl, methyl-substituted phenyl, benzyl or benzoyl;

[0085] R⁷ is H or methyl; or

[0086] R⁵ and R⁶ together form the group (CH₂)₂ or R⁶ and R⁷ together form the group (CH₂)₅ or —(CH)₂—O—(CH₂)₂—;

[0087] c) R⁵ denotes H, alkyl with 1 to 4 carbon atoms, cyclohexyl, methyl-substituted phenyl, benzyl or benzoyl;

[0088] R⁶ denotes H, alkyl with 1 to 3 carbon atoms, cyclohexyl, phenyl, methyl-substituted phenyl or benzyl;

[0089] R⁷ is H or methyl; or

[0090] R⁵ and R⁶ together form the group —(CH₂)₂— or R⁶ and R⁷ together form the group (CH₂)₂—O—(CH₂)₂—;

[0091] d) R⁵ and R⁶ independently of one another denote H, CH₃, CH(CH₃)₂, phenyl or benzyl, R⁷ is H or CH₃, or R⁵ and R⁶ together form the group —CH₂CH₂— or R⁶ and R⁷ together form the group —(CH₂)₂—O—(CH₂)₂—.

[0092] Particularly preferred are compounds of general formula I, wherein X denotes the group

[0093] The following compounds are particularly preferred:

[0094] The compounds may be prepared by methods known per se. Advantageous methods are shown and described in the diagrams which follow.

[0095] The compounds of general formula

[0096] wherein

[0097] X denotes N—R³, wherein R³ is

[0098] may be prepared by reacting a compound of general formula I wherein R³ denotes hydrogen with the corresponding amino-iminomethanesulphonic acid, the corresponding carbodiimide or thiourea. This process is illustrated by methods A to C for compounds wherein Y is CH₂, Ar is phenyl, Z is oxo, R¹ is difluorophenylethyl and R² is methyl. However, the process can be used analogously for all compounds of formula I wherein X is NR³.

[0099] Method A

[0100] Piperazine having a protecting group in the 1 position is reacted with 2-halophenyl-acetate to obtain N-protected piperazinyl-phenylacetate. This is saponified under suitable conditions, e.g. with sodium hydroxide solution, to obtain the corresponding carboxylic acid. This is then linked to an amine according to the invention, e.g. N-methyl-3,5-bis-trifluoromethylphenethyl-amine, using a suitable coupling reagent such as TBTU. In the next step the protecting group is cleaved from the piperazine part of the molecule using a suitable cleaving reagent. In the last step of the reaction, the free piperazine-N is reacted with unsubstituted or substituted amino-iminomethanesulphonic acid (which is obtained for example by oxidation of the corresponding thiourea using H₂O₂) to obtain the desired guanidine.

[0101] Compounds of the type in Examples 1-3 may advantageously be prepared by method A, for example.

[0102] Method B

[0103] The same procedure is used as in method A, except that in the last step, the reaction is carried out with carbodiimides instead of the substituted methanesulphonic acid. These may be either N,N′-disubstituted carbodiimides or N,N,N′-trisubstituted carbodiimides, which are then used in the form of a salt, e.g. the iodide.

[0104] The compounds of the type in Examples 4 to 7 may advantageously be prepared according to method B, for example.

[0105] Method C

[0106] The same procedure is used as in method A, except that in the last step, instead of the substituted methanesulphonic acid, a substituted thiourea is reacted together with H_(g)O.

[0107] Compounds of the type in Example 9 may advantageously be prepared according to method C, for example.

[0108] The compound of general formula

[0109] may also be prepared by reacting the corresponding piperazine derivative or piperidine derivative with the corresponding amide. This process is illustrated by method D and analogous method E for compounds wherein Y denotes CH₂, Ar is phenyl, Z is oxo, R¹ is difluorophenylethyl and R² is methyl. The process may be used analogously, however, for all compounds of formula I wherein X is NR³ or CR⁴. Particularly preferred are compounds wherein

[0110] The reaction is carried out in an inert solvent in the presence of a base.

[0111] Method D

[0112] Analogously to the last step in method A, first of all, piperazine protected in the 1 position is reacted with unsubstituted or substituted amino-iminomethanesulphonic acid. Other substituents may be introduced into the resulting guanidine by alkylation or acylation if required. In the next step the piperazine derivative is obtained with an unsubstituted piperazine-N by cleaving the protecting group with a cleaving reagent.

[0113] The reactant for this piperazine derivative is obtained as shown on the right in Diagram 4. (R)-Mandelic acid is reacted with methanesulphonic acid halide to obtain the (R)-2-(methanesulphonyloxy)-acetic acid. This is then reacted with a coupling reagent and the correspondingly substituted phenethylamine to form the corresponding amide, or it is converted into the corresponding acid halide (e.g. with SOCl₂/SO₂Cl₂) and then converted, with the suitably substituted phenethylamine, into the corresponding amide. In the last step the amide thus obtained is reacted with the piperazine derivative described above, whereupon a C—N bond is formed, with elimination of methanesulphonate, whilst at the same time the chiral centre is reversed. The reaction is carried out in an inert solvent such as e.g. DMF or acetonitrile in the presence of a base such as TEA or N-methylmorpholine, for example, at temperatures between 20° C. and 120° C. The reaction time is between 0.5 h and 48 h.

[0114] Compounds of the type in Example 8 may advantageously be synthesised according to method D.

[0115] The method is carried out analogously to method D. Compounds of the type in Example 36 may advantageously be synthesised according to Method E.

EXAMPLES

[0116]

[0117] (R,S)-1-Amidino-4-[2-phenylacetic acid-N-methyl-N-(3,5-bis-trifluoromethyl-phenyl-ethyl)-amide]-piperazine, dihydrochloride:

[0118] 1.09 g of (R,S)-1-[2-phenylacetic acid-N-methyl-N-(3,5-bis-trifluoromethyl-phenylethyl)-amide]-piperazine (2 mmol) were mixed with 5 ml of water, 5 ml of methanol, 1.1 g of K₂CO₃ (8 mmol) and 0.5 9 of aminoimino-methanesulphonic acid (4 mmol) and stirred for 2 days at RT. The reaction mixture was diluted with water and extracted several times with EE and ether. The organic phases were combined, dried with MgSO₄ and evaporated to dryness. The solid residue was chromatographed over silica gel and the fractions found to be uniform by DC were combined and evaporated to dryness. The residue was dissolved in methanol, mixed with ethereal HCl, evaporated to dryness, stirred with ether, suction filtered and dried. 80 mg of the compound of Example 1 are obtained (yield 7%).

[0119] melting point: 128-138° C.

[0120] FAB-MS: (M+H)⁺=516.4.

[0121] Examples 2 and 3 were prepared analogously:

[0122] melting point: 163-173° C.

[0123] FAB-MS: (M+H)⁺=542.2.

[0124] melting point: 69-79° C.

[0125] FAB-MS: (M+H)⁺=530.2.

[0126] 0.82 g of (R,S)-1-[2-phenylacetic acid-N-methyl-N-(3,5-bis-trifluoromethyl-phenylethyl)-amide]-piperazine were mixed with 20 ml of CH₂Cl₂, 0.5 ml of TEA and 0.215 g of N,N′-diisopropylcarbodiimide and the reaction mixture was stirred for 4 days at RT. It was then evaporated to dryness and the residue was chromatographed over silica gel. The fractions found to be uniform by DC were combined and concentrated by evaporation, the residue was taken up in methanol, mixed with ethereal HCl and again evaporated to dryness. The solid residue was stirred with ether, suction filtered and dried, to obtain 0.35 g of the compound of Example 4 as a racemate (yield 35%).

[0127] melting point: 176-186° C. (decomp.)

[0128] FAB-MS: (M+H)⁺=600.6.

[0129] Examples 5 to 7 were prepared analogously to Example 4.

[0130] melting point: 174-184° C. (decomp.)

[0131] FAB-MS: (M+H)⁺=600.6.

[0132] melting point: 145-158° C.

[0133] [α]_(D) ²⁰=24.8° (DMSO)

[0134] melting point: 182-188° C. (decomp.)

[0135] FAB-MS: (M+H)⁺=680.3.

Preparation of 1-(1-methyl-imidazolin-2-yl)-piperazine

[0136] 1.86 of Boc-piperazine were combined with 25 ml of water, 25 ml of methanol, 2.77 g of K₂CO₃ and 1.5 g of imidazoline-2-sulphonic acid and stirred for 2 days at RT. After dilution with water the mixture was extracted with EE and chromatographed over silica gel. 0.8 g of 1 (imidazolin-2-yl)-4-Boc-piperazine were obtained. This substance was combined with 6.2 ml of DMF and 136 mg of NaH dispersion (60%). After one hour, 0.214 ml of methyl iodide was added dropwise and the reaction mixture was left for three days at RT. It was combined with water, extracted with EE and chromatographed over silica gel. In this way, 0.47 g of 1-(1-methylimidazolin-2-yl)-4-Boc-piperazine was obtained, which was treated with 5 ml of 4N HCl in dioxane at RT. After one hour, the mixture was concentrated by evaporation, stirred with ether and evaporated to dryness in vacuo. 0.38 g of 1-(1-methyl-imidazolin-2-yl)-piperazine dihydrochloride was thus obtained as a solid substance (yield 15%).

[0137] 0.73 g of (R)-mandelic acid-O-methanesulphonate-N-methyl-N-(3,5-bistrifluoromethylphenylethyl)-amide was combined with 15 ml of DMF, 0.7 ml of TEA and 0.38 g of 1-(1-methyl-imidazolin-2-yl)-piperazine dihydrochloride and stirred for 3 h at 65° C. The reaction mixture was evaporated down, the residue was first treated with NaHCO₃ solution and then extracted twice with EE. The organic phases were combined, concentrated by evaporation under reduced pressure and the residue was chromatographed over silica gel. The product thus obtained was dissolved in ether, washed with NaHCO₃, and evaporated to dryness with MgSO₄.

[0138] The residue was dissolved in methanol, mixed with excess ethereal HCl and evaporated to dryness, to obtain 0.18 g of the compound of Example 8 (yield 19%).

[0139] melting point: 115-125° C.

[0140] FAB-MS: (M+H)⁺=556.9.

[0141] 0.31 g of N,N′-dimethylthiourea, 26 ml of CH₂Cl₂, 0.63 g of Na₂SO₄, 1.25 g of HgO 0.77 g of (S)-1-[2-phenylacetic acid-N-methyl-N-(3,5-bistrifluoromethyl-phenylethyl)-amide]-piperazine and 0.42 ml of TEA were combined, stirred for 3 days at RT and then refluxed for 4 hours. The reaction mixture was concentrated by evaporation under reduced pressure and the residue was treated with water and EE. The organic phase separated off was filtered and evaporated to dryness. The residue was chromatographed over silica gel. The eluate obtained was evaporated down, dissolved in methanol, mixed with ethereal HCl, evaporated to dryness once more, the residue was washed with ether and dried. 0.15 g of the compound of Example 9 was obtained as a white solid (yield 16%).

[0142] melting point: 126-140° C.

[0143] FAB-MS: (M+H)⁺=543.8.

[0144] melting point: 131-141° C.

[0145] [α]_(D) ²⁰=20.60 (DMSO)

[0146] The Examples which follow may be prepared using the methods described.

[0147] (+)-enantiomer melting point: 171-181° C.

[0148] [α]20/D=28.4° (DMSO).

[0149] melting point: 240-245° C. (decomp.)

[0150] FAB-MS: (M+H)⁺=592.1.

[0151] (+)-enantiomer FAB-MS: (M+H)⁺=584.

[0152] melting point: 124-128° C. FAB-MS: (M+H)⁺=648.2

[0153] melting point: 193-198° C. FAB-MS: (M+H)⁺=696.4.

[0154] [α]_(D) ²⁰=+50.0° (DMSO)

[0155] melting point: 146-149° [α]_(D) ²⁰=+48.8° (DMSO)

[0156] melting point: 90-100° [α]_(D) ²⁰=+23.6° (DMSO)

[0157] melting point: 170-180° FAB-MS: (M+H)⁺=661.9

[0158] melting point: 84-94° [α]_(D) ²⁰=20.4° (DMSO)

[0159] melting point: 169-179° [α]_(D) ²⁰=43.6° (DMSO)

[0160] melting point: 131-141° [α]_(D) ²⁰=+25.2° (DMSO)

[0161] melting point:146-148° FAB-MS: (M+H)⁺=584, 586, 588

[0162] melting point: 126-134° C.

[0163] 3.8 g of 4-amino-1-benzylpiperidine (20 mmol) was combined with 4.7 g of dicyclohexylcarbodiimide (23 mmol) in 80 ml of DMF and stirred for 12 hours at 80° C. The solvent was evaporated in vacuo and the residue was flash chromatographed using ethyl acetate/methanol (1:1) whereby 54. g of 1-benzyl-4(N′, N″-dicyclohexyl-guanidino)-piperidine was obtained (71%). 5 g of the product (12.6 mmol) was dissolved in 60 ml of methanol and hydrogenated using 0.6 g of Pd(C) at 2 bar hydrogen pressure. Thus obtained was 4 g of 4(N′, N″-dicyclohexyl-guanidino)-piperidine (63%)

[0164] 2.14 g of the product (7 mmol) was combined with 2.9 g of (R)-2-methylsulphonyloxy-N-methyl-N-[2-(3,5-bistrifluoromethyl-phenyl)-ethyl]-phenylacetamide (6 mmol), 60 ml of DMF and 0.96 ml of triethylamine and stirred for 3 hours at 65° C. The residue obtained after concentrating the raw product was chromatographed over silica gel with ethyl acetate/methanol (1:1) as an eluant, whereupon 0.6 g of the desired substance was obtained.

[0165] melting point: 114-124° C.

[0166] [α]20/D=41.4° (DMSO)

[0167] Pharmaceutical Preparations Injectable solution 200 mg of active substance *  1.2 mg of monopotassium dihydrogen phosphate = KH₂PO₄ )  0.2 mg of disodium hydrogen phosphate ) (buffer) = NaH₂PO₄.2H₂O )  94 mg of sodium chloride ) (for an isotonic solution) or ) 520 mg of glucose )  4 mg of albumin (protease protection) q.s. sodium hydroxide solution) q.s. hydrochloric acid ) ad pH 6 ad 10 ml water for injections Injectable solution 200 mg of active substance*  94 mg of sodium chloride or 520 mg of glucose  4 mg of albumin q.s. sodium hydroxide solution ) q.s. hydrochloric acid ) ad pH 9 ad 10 ml water for injections Lyophilisate 200 mg of active substance * 520 mg of mannitol (for isotonic solution/bulking agent)  4 mg of albumin solvent 1 for lyophilisate  10 ml water for injections solvent 2 for lyophilisate  20 mg Polysorbate 200 80 = Tween ® 80 (surfactant)  10 ml water for injections

[0168] Dosage for person weighing 67 kg: 1 to 500 mg 

What is claimed is:
 1. A process for the preparation of a compound of formula

wherein R⁵, R⁶, R⁷ independently of one another denote H, alkyl, cycloalkyl, alkenyl, aryl, aralkyl, alkanoyl, benzoyl, heteroaryl, dialkylamino, dialkylaminoalkyl, trialkylammoniumalkyl, cyano, alkyloxycarbonyl, aralkyloxycarbonyl, OH, O-alkyl or O-aryl, wherein the alkyl groups contain 1 to 5 carbon atoms, the cycloalkyl groups contain 3 to 6 carbon atoms, the alkenyl groups contain 2 to 5 carbon atoms, aryl denotes phenyl, or phenyl or naphthyl substituted by methyl or halogen; or R⁵ and R⁶ or R⁶ and R⁷ together form the group (CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅— or —(CH₂)₂O(CH₂)₂; and R⁸ represents H, alkyl with 1 to 5 carbon atoms or cycloalkyl with 3 to 6 carbon atoms or R⁷+R⁸ together form the group —(CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—, —(CH₂)₅— or —(CH₂)₂O(CH₂)₂—; which process comprises reacting an amide of formula

with a piperidine of formula

to produce a compound of the formula identified hereinabove; wherein R⁵ ₁, R⁶, R⁷ and R⁸ have the meaning given above.
 2. An intermediate compound of formula


3. A process for the preparation of a compound of formula

which process comprises the steps of: (a) reacting (R)-mandelic acid with methanesulphonic acid halide to obtain (R)-2-Methanesulphonyloxy)-2-phenylacetic acid, and (b) reacting said (R)-2-Methanesulphonyloxy)-2-phenylacetic acid with a coupling reagent of formula

to produce a compound of the formula identified hereinabove.
 4. A compound wherein the compound is 